Field of the Invention
The present inventions relate to at least one image processing apparatus, at least one image processing method, and at least one imaging apparatus that provide a blurring processing function.
Description of the Related Art
When capturing an image, a compact digital camera focuses on a relatively wider distance range than a single-lens reflex camera. Therefore, the compact digital camera cannot capture an image having a largely blurred background, which can be performed by the single-lens reflex camera. For this reason, digital filter processing has been conventionally performed by the compact digital camera, to obtain a large blurring effect. In the digital filter processing, a blur equivalent to a blur obtained by the single-lens reflex camera is applied to a captured image. For example, Japanese Patent Application Laid-Open No. 2004-102904 discusses a technique for providing an image with a large blur by performing small-size filter processing. In this technique, the small-size filter processing is performed on a reduced image, and the reduced image is then enlarged to an original size.
However, the conventional technique discussed in Japanese Patent Application Laid-Open No. 2004-102904 cannot precisely reproduce a blur similar to a background blur produced by the single-lens reflex camera, due to a small filter size. For example, there is an image-capturing method for forming a large round blur on a point light source in a background, when using a single-lens reflex camera. However, details of the shape of the round blur cannot be sufficiently expressed by performing the small-size filter processing discussed in Japanese Patent Application Laid-Open No. 2004-102904, because a high-frequency component of the image is lost by the reduction of the image. If the filter processing without reducing an image is performed to reproduce a large blur similar to a background blur produced by the single-lens reflex camera, a multiple-tap two-dimensional filter of about 50 taps is required. When this filter is implemented on a circuit, a circuit scale becomes considerably large.
The present inventions are directed to at least one image processing apparatus, at least one image processing method and at least one imaging apparatus capable of precisely reproducing a large blur similar to a background blur produced by a single-lens reflex camera, while suppressing a circuit scale of the filter processing.